Pre‐pregnancy BMI, physical activity and resting energy expenditure predicts body composition in pregnancy

Abstract

A high proportion of women exceed gestational weight gain (GWG) recommendations, but the body composition of women and factors influencing these changes are not explicit. The study objective was to describe the association between pre‐pregnancy body mass index (BMI), lifestyle factors, resting energy expenditure (REE) and fat mass (FM) accretion during pregnancy. Pregnant women (n=600) were measured 2–3 times during pregnancy; data on weight, body composition (skin folds), diet (24 hour recall) and physical activity (questionnaire) were collected. Data was analysed by linear mixed regression. Women with normal and overweight BMI gained similar amounts of total FM while obese women gained less FM and had a slower rate of FM accretion (p<0.01). Sports score was inversely associated with FM (p<0.01), while REE was positively associated with FM (p<0.01). In longitudinal analyses, overweight and obese women had lower sports scores (p<0.05) and higher REE (p<0.01) compared to women with normal BMI. Energy and macronutrient intake did not differ among BMI groups. Energy intakes in overweight and obese women were less than their estimated energy requirements (p<0.01). Effective intervention programs promoting optimal GWG should account for variations in individual woman's energy expenditure. Future studies estimating energy intake requirements during pregnancy according to pre‐pregnancy BMI are warranted.Grant Funding Source: Alberta Innovates‐Health Solutions